| /* |
| * Copyright (C) 2014 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.tools.lint.checks; |
| |
| import com.android.annotations.NonNull; |
| import com.android.annotations.Nullable; |
| import com.android.tools.lint.detector.api.Category; |
| import com.android.tools.lint.detector.api.ConstantEvaluator; |
| import com.android.tools.lint.detector.api.Detector; |
| import com.android.tools.lint.detector.api.Implementation; |
| import com.android.tools.lint.detector.api.Issue; |
| import com.android.tools.lint.detector.api.JavaContext; |
| import com.android.tools.lint.detector.api.Scope; |
| import com.android.tools.lint.detector.api.Severity; |
| import com.google.common.collect.Sets; |
| import com.intellij.psi.JavaElementVisitor; |
| import com.intellij.psi.PsiElement; |
| import com.intellij.psi.PsiExpression; |
| import com.intellij.psi.PsiExpressionList; |
| import com.intellij.psi.PsiLiteral; |
| import com.intellij.psi.PsiMethod; |
| import com.intellij.psi.PsiMethodCallExpression; |
| |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Set; |
| |
| /** |
| * Ensures that Cipher.getInstance is not called with AES as the parameter. |
| */ |
| public class CipherGetInstanceDetector extends Detector implements Detector.JavaPsiScanner { |
| public static final Issue ISSUE = Issue.create( |
| "GetInstance", //$NON-NLS-1$ |
| "Cipher.getInstance with ECB", |
| "`Cipher#getInstance` should not be called with ECB as the cipher mode or without " + |
| "setting the cipher mode because the default mode on android is ECB, which " + |
| "is insecure.", |
| Category.SECURITY, |
| 9, |
| Severity.WARNING, |
| new Implementation( |
| CipherGetInstanceDetector.class, |
| Scope.JAVA_FILE_SCOPE)); |
| |
| private static final String CIPHER = "javax.crypto.Cipher"; //$NON-NLS-1$ |
| private static final String GET_INSTANCE = "getInstance"; //$NON-NLS-1$ |
| private static final Set<String> ALGORITHM_ONLY = |
| Sets.newHashSet("AES", "DES", "DESede"); //$NON-NLS-1$ |
| private static final String ECB = "ECB"; //$NON-NLS-1$ |
| |
| // ---- Implements JavaScanner ---- |
| |
| @Nullable |
| @Override |
| public List<String> getApplicableMethodNames() { |
| return Collections.singletonList(GET_INSTANCE); |
| } |
| |
| @Override |
| public void visitMethod(@NonNull JavaContext context, @Nullable JavaElementVisitor visitor, |
| @NonNull PsiMethodCallExpression node, @NonNull PsiMethod method) { |
| if (!context.getEvaluator().isMemberInSubClassOf(method, CIPHER, false)) { |
| return; |
| } |
| PsiExpressionList argumentList = node.getArgumentList(); |
| PsiExpression[] arguments = argumentList.getExpressions(); |
| if (arguments.length == 1) { |
| PsiExpression expression = arguments[0]; |
| Object value = ConstantEvaluator.evaluate(context, expression); |
| if (value instanceof String) { |
| checkParameter(context, node, expression, (String)value, |
| !(expression instanceof PsiLiteral)); |
| } |
| } |
| } |
| |
| private static void checkParameter(@NonNull JavaContext context, |
| @NonNull PsiMethodCallExpression call, @NonNull PsiElement node, @NonNull String value, |
| boolean includeValue) { |
| if (ALGORITHM_ONLY.contains(value)) { |
| String message = "`Cipher.getInstance` should not be called without setting the" |
| + " encryption mode and padding"; |
| context.report(ISSUE, call, context.getLocation(node), message); |
| } else if (value.contains(ECB)) { |
| String message = "ECB encryption mode should not be used"; |
| if (includeValue) { |
| message += " (was \"" + value + "\")"; |
| } |
| context.report(ISSUE, call, context.getLocation(node), message); |
| } |
| } |
| } |